In the conventional manner of playing stringed instruments such as guitars, banjos and the like, strings are pressed against frets on a fretboard or against a fretless fingerboard in order to vary the active string length and thus select the pitch (i.e. frequency) of the note to be played; normally the left hand forms notes and chords while the strings are picked, plucked, strummed or bowed with the right hand which predominantly controls amplitude envelope parameters, particularly the dynamics of each note, such as attack and loudness. This basic approach has been carried over from the purely acoustic category of instruments to the great majority of electronically-amplified stringed instruments in present use, notably the amplified "electric guitar". Even in the more technically sophisticated category of "guitar synthesizers" this traditional string-and-fret system is commonly utilized as the actual interface with the musician; string vibrations are sensed in an pickup whose analog electrical output is converted to a "synthesizer language" such as MIDI, the widely adopted Musical Instrument Digital Interface standards, for further electronic processing into synthesized sounds.
In a departure from the conventional approach of fingering the strings with one hand while strumming or plucking strings with the other hand, a stringed instrument trademarked as The Chapman Stick, introduced in 1974 and disclosed in U.S. Pat. Nos. 3,833,751 and 3,868,880 to Chapman, is played with both hands on the fingerboard; a musical note is initiated by tapping a string against a fret with either hand as opposed to strumming or plucking. This playing technique in conjunction with magnetic string pickups has been practiced using The Stick with analog power amplification and in a synthesizer controller version, trademarked as The Grid, where the pickup signals are MIDI-encoded to facilitate a variety of digital/analog electronic effects. A LAYERED VOICE MUSICAL SELF ACCOMPANIMENT METHOD, for which The Stick and The Grid are particularly well suited, is disclosed in U.S. Pat. No. 4,922,797 to Chapman.
A special requirement of two-handed string tapping technique as taught by Chapman is the need for control over the amplitude envelope, for musical expression, at the same fingertip interface, i.e. the fingerboard, which provides the basic function of pitch selection as each note is played with either hand at the fretboard; this is a fundamental departure from conventional techniques where one hand normally provides pitch selection at the fingerboard while the other hand is mainly dedicated to forming and controlling the amplitude and expression through strumming, picking or plucking motions.
The difficulties and limitations of manufacturing, maintaining and playing conventional string-and-fret instruments are well known, and have prompted numerous efforts to develop alternative approaches which exploit the capabilities of electronic technology. The concept of a stringless fingerboard implemented by electronics overcomes many of these difficulties and limitations which are inherently mechanical in origin. Electronic technology has provided the potential of greatly enhanced control over the various amplitude envelope parameters such as attack, decay, sustain and release, which in mechanical acoustic instruments are subject to severe limitations imposed by the mechanical constraints of the string-and-fret instrument and require a great deal of practice and skill on the part of the player in attempting to develop a degree of control over the envelope through a combination of fingerboard technique with one hand and picking/plucking/bowing technique with the other hand. The ease with which electronics can control envelope parameters in real time facilitates implementation of the concept of a two-handed playing technique wherein a wide range of envelope control capability is provided instantly at each fingertip by advanced human-machine interfacing at a stringless playing surface.
"Stringless" fingerboards which have been proposed in known art have predominantly addressed only the conventional techniques of using only one hand on the fingerboard for selecting pitch. Within this category, U.S. Pat. Nos. 4,339,979 to Norman, 4,177,705 to Evangelista, and 3,340,343 to Woll require some form of strumming or plucking to be performed by one hand, while in U.S. Pat. Nos. 3,555,166 .to Gasser and 4,570,521 to Fox, a piano-type keyboard is to be played by one hand while the other plays the fingerboard or fretboard. Eventoff U.S. Pat. Nos. 4,235,141 and Suzuki et al 3,694,559 disclose fingerboards in which pitch is varied by variable resistance. These approaches and others of known art have been directed to one-handed fingerboard techniques which utilize the fingerboard solely for pitch selection, and thus have failed to address fingerboard control of amplitude envelope parameters, in particular attack velocity, as required for two-handed fingerboard techniques addressed by the present invention.
In playing conventional string-and-fret type instruments, musicians often use a technique known as "pitch bending": a note which has been selected by holding a string against a fret is "bent", i.e. shifted to a higher pitch, by pushing the string laterally along the fret in either direction from its normal position so as to increase the string tension and thus increase the resonant vibration frequency of the string. The pitch cannot be bent to a lower pitch in this manner; however, as a partial remedy to this shortcoming, some instruments are provided with a string tensioning lever, usually operated by the plucking/strumming hand, by which the overall string tension can be varied in either direction, affecting all the strings. This inability to bend the pitch of individual strings downward using the string-and-fret hand is clearly an inherent limitation imposed by the mechanical nature of conventional instruments, and has not been heretofore remedied by known art in either stringed or stringless approaches.
The mechanics of the conventional string-and-fret fingerboard basically restricts finger control to only two dimensions: (1) downwardly, as the string is pressed against a fret in a virtually binary (i.e. on-off) function, and (2) laterally, as the string is stretched sideways to obtain a limited and inflexible degree of upward pitch bending in either of the two opposed lateral directions. However the player's fingers, if suitably interfaced, are capable of movements in other directions which may be utilized advantageously to control various musical effects or parameters such as sustain, reverberation, timbre, etc., directly at the player's fingertips, in a significant extension of the conventional playing techniques of simple note selection and limited pitch bending.